[TowerTalk] book Tribander comparison test

[Joe Subich, W4TV]

 > The same with Force 12  net gain figures.

The Force 12 "net gain" numbers are not field verified.  They are
"model values" derived at a specific height (74 feet) and are the
maximum gain for the antenna - not an average across the band.
In addition to the difference between average and maximum gain -
which was as much as 1.4 dB in the N0AX/K7LXC tests, using a
different height in the Force 12 models will introduce another
error that can be a significant fraction of a dB (do the dipole
vs. 3 element Yagi comparisons for varying heights over high
precision ground in EZNEC).

Since the variations between the better performing antennas in a
given "class" are less than 1.5 dB, the Force 12 "net gain"
figures can not be used for comparison.  In fact, the "net gain"
numbers published by Force 12 for the C3 and C31XR are 15 to 20%
higher than *peak* values given in the the 2nd edition of the
N0AX/K7LXC report.

73,

    ... Joe, W4TV


On 2/24/2011 12:29 PM, K7LXC at aol.com wrote:
>
> In a message dated 2/24/2011 5:39:10 A.M. Pacific Standard Time,
> towertalk-request at contesting.com writes:
>
>>   I would echo Chris' suggestion and perhaps add the  Optibeam 16-5 and
> the
> SteppIR 4-element to your updated list of beam  antennas to test and rate
> in
> your HF TRIBANDER PERFORMANCE - TEST METHODS&  RESULTS .  It was a great
> review article that I wish could be  updated with new antenna models.
>
>
>      Well, I'm with you on that one. Unfortunately the  cost for the
> antennas and the time needed to assemble them, conduct the tests  and then write
> them up takes more commitment than we have now.
>
>      OTOH ANYONE can take our protocol and run  additional tests that will
> meld right in with what's already been done. Any  volunteers?
>
>      As far as the SteppIR, it's a monobander for all  practical purposes.
> Fluid Motion has published gain figures using our protocol  so their results
> can be compared directly with ours. The same with Force 12  net gain
> figures.
>
> Cheers,
> Steve     K7LXC
> TOWER TECH
> and
> Champion Radio Products
>
>
>
>
>
>
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